1. Field of the Invention
The present invention relates to a device for positioning a sheet member in a state in which the sheet member is placed on a generally flat plate, and to a device for recording an image onto a printing plate.
2. Description of the Related Art
A printing plate exposure device has been developed which exposes and records an image directly by a laser beam or the like onto a photosensitive layer on a support of a sheet-shaped printing plate such as, for example, a photo-polymer plate or a thermal plate. The photosensitive layer includes the emulsion surface of the printing plate.
In such a printing plate exposure device, the printing plate placed on a generally flat plate is, as needed, conveyed to a punching section, and is subjected to punching processing thereat. This punching processing is a processing for forming punch holes to be used for positioning the printing plate in printing processing which is a process to be carried out later. Further, the printing plate placed on the plate is conveyed to an exposure section, and exposure processing of the printing plate is carried out at the exposure section.
Here, before the punching processing in the punching section and the exposure processing in the exposure section, in order to improve the accuracy of the punching processing and the exposure processing, the printing plate must be positioned while being restrained or being held by pressure being applied thereto, in a state in which the printing plate is placed on the plate. Here, when the printing plate is restrained or held by the application of pressure, parameters, which enable the printing plate to be restrained or held by pressure such that it is difficult for the printing plate to buckle, are determined in advance by experimentation. On the basis of these parameters, the printing plate is restrained or is held by pressure being applied thereto.
The following is an example of positioning the printing plate while restraining or holding by pressure the printing plate which is in a state of being placed on a plate. Two first reference pins are provided at a side of the plate in one direction, which is the punching section side or the exposure section side of the plate. The printing plate is pushed by a first moving pin until the printing plate abuts the two first reference pins. The position of the printing plate in the one direction is thereby determined. Moreover, one second reference pin is provided at a side of the plate in another direction which is orthogonal to the aforementioned one direction. The printing plate is pushed by a second moving pin until the printing plate abuts the second reference pin. The position of the printing plate in this other direction is thereby determined.
There is also a method of positioning in which cut-outs are formed in the printing plate simultaneously with the punching processing in the punching section. With the first reference pins inserted into these cut-outs, positioning of the printing plate is carried out in the same manner as described above.
However, in such a printing plate exposure device, as described above, parameters, which make it difficult for the printing plate to buckle, are determined in advance by experimentation, and the printing plate is restrained or is held by pressure being applied thereto. Thus, there is the problem that the force of restraining the printing plate or the force of the holding by pressure of the printing plate is small, and the accuracy of positioning is unstable. The force of holding by pressure is, for example, the force of pushing the printing plate by the first moving pin and the second moving pin. The positioning accuracy being unstable means, for example, that the printing plate cannot reliably abut the first reference pins or the second reference pin. On the other hand, if the restraining force or the pressure holding force for holding the printing plate to the plate is increased, buckling deformation of the printing plate arises and the positioning accuracy deteriorates.
When cut-outs are formed in the printing plate, even if there is curving at the end surfaces of the printing plate, the printing plate can be accurately positioned. However, an expensive device for forming cut-outs is required, and the manufacturing costs thereby rise.
When two printing plate moving mechanisms are required such as in the case in which a first moving pin and a second moving pin are provided at the plate, the costs increase and the device becomes larger.
Before exposure processing at the exposure section, the printing plate is positioned in a state of being placed on the plate, and the exposure start position of the printing plate is determined. It is therefore necessary for the exposure position of the printing plate to coincide with the printing position of the printing plate determined by the punch holes.
Here, a first method for determining the exposure position of the printing plate is the following method. Simultaneously with the punching processing the punching section, cut-outs are formed in the printing plate. Insertion pins, which are fixed at the exposure section, are inserted into these cut-outs, and the printing plate is positioned. Further, on the basis of parameters set in advance for respective printing plate sizes, the exposure position of the printing plate is determined.
As a second method for determining the exposure position of the printing plate, there is a method in which end surfaces of a predetermined printing plate, which has been positioned in the exposure section by a method in which cut-outs are not formed in the printing plate, are detected optically. The exposure position of the printing plate is determined by computation from the results of detection.
However, in the above-described first method, there is the need to form cut-outs in the printing plate. Accordingly, an expensive device for forming cut-outs is required, and the device becomes expensive on the whole.
In the above-described second method, because the end surfaces of a printing plate curve slightly at each printing plate, the exposure position of the printing plate cannot be made to accurately coincide with the printing position. Thus, at the time of printing processing of the printing plate, the printing position must be made to match the exposure position by adjusting the printing position on the basis of the exposure position of the printing plate.
In view of the aforementioned, an object of the present invention is to provide a device for positioning a sheet member which can improve the accuracy of positioning a sheet member.
Another object of the present invention is to provide a device for positioning a sheet member and an image recording device which are low cost and in which, even if the end surfaces of a sheet member or a printing plate are curved, a position at which the sheet member or the printing plate is positioned by a first abutment member and a third abutment member, and a position at which the sheet member or the printing plate is positioned by a second abutment member and the third abutment member, can be made to coincide.
A first aspect of the present invention is a device for positioning a sheet member, the device comprising: a generally flat plate on which the sheet member is received; a conveying device provided so as to correspond to the sheet member received on the plate, and conveying the sheet member in the first direction; a temporary abutment member provided at a side of the plate in the first direction, and due to the sheet member, being conveyed in the first direction, the sheet member abutting the temporary abutment member at at least two points, which determines a position of the sheet member in a temporary direction; an actual abutment member provided at that side of the plate, and due to the sheet member being conveyed in the first direction after the position in the temporary direction has been determined, the sheet member abutting the actual abutment member at at least two points, which determines a position of the sheet member in an actual direction; a conveying force applying device applying a conveying force to the sheet member in the second direction substantially orthogonal to the first direction, to the sheet member; and a reference abutment member provided at another side of the plate in the second direction, and due to the conveying force in the second direction being applied to the sheet member, the sheet member abutting the reference abutment member, which determines a position of the sheet member in the second direction, wherein an angle of inclination of the temporary direction with respect to the first direction is xcex1, and an angle of inclination of the actual direction with respect to the first direction is xcex2, xcex1 less than xcex2.
In the device for positioning a sheet member of the first aspect of the present invention, the position of the sheet member in the temporary direction is determined by the conveying device conveying the sheet member on the plate in the first direction and the sheet member abutting the temporary abutment member at at least two points. The position of the sheet member in the actual direction is determined by the conveying device conveying, in the first direction, the sheet member after the position thereof in the temporary direction has been determined, and the sheet member abutting the actual abutment member at at least two points.
Due to conveying force in the other direction being applied to the sheet member by the conveying force applying device and the sheet member abutting the reference abutment member, the position of the sheet member in the other direction is determined.
In this way, due to the position of the sheet member in the actual direction and the other direction being determined, the sheet member is positioned in a state of being placed on the plate. This positioned state can be maintained by the force of conveying the sheet member by the conveying device and the conveying force applying device.
Here, given that an angle of inclination of the temporary direction with respect to the first direction is xcex1, and an angle of inclination of the actual direction with respect to the first direction is xcex2, xcex1 less than xcex2. Thus, the sheet member, which is being conveyed in the first direction after the position thereof in the temporary direction has been determined, first abuts the actual abutment member at one point and is pivoted. The sheet member thereby abuts the actual abutment member at at least two points, and the position of the sheet member in the actual direction is determined.
In this way, the sheet member is pivoted and abuts the actual abutment member at at least two points, and the sheet member abuts the reference abutment member due to the conveying force applying device. Thus, the sheet member can reliably abut the actual abutment member at at least two points, and can reliably abut the reference abutment member. The accuracy of positioning the sheet member can thereby be improved.
In the device for positioning a sheet member of the first aspect of the present invention, usually, before the sheet member abuts at least one of the temporary abutment member and the actual abutment member, the conveying device reduces a conveying speed of the sheet member.
In the device for positioning a sheet member of the present invention having such a conveying device, the conveying device reduces the conveying speed of the sheet member before the sheet member abuts at least one of the temporary abutment member and the actual abutment member. Thus, it is possible to suppress the moving away of the sheet member from the temporary abutment member or the actual abutment member due to the reaction of abutting the temporary abutment member or the actual abutment member. In this way, the sheet member can even more reliably abut the temporary abutment member and the actual abutment member, and the accuracy of positioning the sheet member can be improved even more.
A device for positioning a sheet member of a second aspect of the present invention comprises: a generally flat plate on which a sheet member is received; a conveying device provided so as to correspond to the sheet member received on the plate, and conveying the sheet member in one direction; a first temporary abutment member provided at a side of the plate in the first direction, and due to the sheet member being conveyed in the first direction, the sheet member abutting the first temporary abutment member at at least two points, which determines a position of the sheet member in a first temporary direction; a first actual abutment member provided at that side of the plate, and due to the sheet member being conveyed in the first direction after the position in the first temporary direction has been determined, the sheet member abutting the first actual abutment member at at least two points, which determines a position of the sheet member in a first actual direction; a second temporary abutment member provided at that side of the plate, and due to the sheet member being conveyed in the first direction after the position in the first actual direction has been determined, the sheet member abutting the second temporary abutment member at at least two points, which determines a position of the sheet member in a second temporary direction; a second actual abutment member provided at that side of the plate, and due to the sheet member, which is being conveyed in the first direction after the position in the second temporary direction has been determined, the sheet member abutting the second actual abutment member at at least two points, which determines a position of the sheet member in a second actual direction; a conveying force applying device applying a conveying force to the sheet member in the second direction, substantially orthogonal to the first direction; and a reference abutment member provided at another side of the plate in the second direction, and due to the conveying force in the second direction being applied to the sheet member, the sheet member abutting the reference abutment member, which determines a position of the sheet member in the second direction, wherein given that an angle of inclination of the first temporary direction with respect to the first direction is xcex11, an angle of inclination of the first actual direction with respect to the first direction is xcex21, an angle of inclination of the second temporary direction with respect to the first direction is xcex12, and an angle of inclination of the second actual direction with respect to the first direction is xcex22, when xcex11xe2x89xa0xcex12, xcex11 less than xcex21 less than xcex12 less than xcex22, and when xcex11=xcex12, xcex11 less than xcex21 and xcex12 less than xcex22.
In the device for positioning a sheet member of the second aspect of the present invention, the position of the sheet member in the first temporary direction is determined by the conveying device conveying the sheet member on the plate in the first direction and the sheet member abutting the first temporary abutment member at at least two points. Further, the position of the sheet member in the first actual direction is determined by the conveying device conveying, in the first direction, the sheet member after the position thereof in the first temporary direction has been determined, and the sheet member abutting the first actual abutment member at at least two points.
Moreover, the position of the sheet member in the second temporary direction is determined by the conveying device conveying, in the first direction, the sheet member after the position thereof in the first actual direction has been determined, and the sheet member abutting the second temporary abutment member at at least two points. In addition, the position of the sheet member in the second actual direction is determined by the conveying device conveying, in the first direction, the sheet member after the position thereof in the second temporary direction has been determined, and the sheet member abutting the second actual abutment member at at least two points.
The position of the sheet member in the other direction is determined by conveying force in the other direction being applied to the sheet member by the conveying force applying device, and the sheet member abutting the reference abutment member.
In this way, the position of the sheet member in the first actual direction and the other direction is determined, or the position of the sheet member in the second actual direction and the other direction is determined. Thus, in either case, the sheet member can be positioned in a state in which it is placed on the plate, and this positioned state can be maintained by the force of conveying the sheet member due to the conveying device and the conveying force applying device.
Here, given that an angle of inclination of the first temporary direction with respect to the first direction is xcex11, an angle of inclination of the first actual direction with respect to the first direction is xcex21, an angle of inclination of the second temporary direction with respect to the first direction is xcex12, and an angle of inclination of the second actual direction with respect to the first direction is xcex22, when xcex11xe2x89xa0xcex12, xcex11 less than xcex21 less than xcex12 less than xcex22, and when xcex11=xcex12, xcex11 less than xcex21 and xcex12 less than xcex22. Thus, the sheet member, which is being conveyed in the first direction after the position thereof in the first temporary direction has been determined, first abuts the first actual abutment member at one point and is pivoted. The sheet member thereby abuts the first actual abutment member at at least two points, and the position of the sheet member in the first actual direction is determined. Moreover, the sheet member, which is being conveyed in the first direction after the position thereof in the second temporary direction has been determined, first abuts the second actual abutment member at one point and is pivoted. The sheet member thereby abuts the second actual abutment member at at least two points, and the position of the sheet member in the second actual direction is determined.
In this way, the sheet member is pivoted, abuts the first actual abutment member and the second actual abutment member at at least two points, and abuts the reference abutment member due to the conveying force applying device. Thus, the sheet member can reliably abut the first actual abutment member and the second actual abutment member at at least two points, and can reliably abut the reference abutment member. The accuracy of positioning the sheet member can thereby be improved.
As described above, when xcex11xe2x89xa0xcex12, xcex21 less than xcex12. Thus, the sheet member, which is being conveyed in the first direction after the position thereof in the first actual direction has been determined, first abuts the second temporary abutment member at one point and is pivoted. The sheet member thereby abuts the second temporary abutment member at at least two points, and the position of the sheet member in the second temporary direction is determined. Thus, the sheet member can reliably abut the second temporary abutment member at at least two points. In this way, the sheet member can even more reliably abut the second actual abutment member at at least two points, and the accuracy of positioning the sheet member can be reliably improved.
In the device for positioning a sheet member of the second aspect of the present invention, usually, before the sheet member abuts at least one of the first temporary abutment member, the first actual abutment member, the second temporary abutment member, and the second actual abutment member, the conveying device reduces a conveying speed of the sheet member.
In the device for positioning a sheet member of the present invention having such a conveying device, the conveying device reduces the conveying speed of the sheet member before the sheet member abuts at least one of the first temporary abutment member, the first actual abutment member, the second temporary abutment member, and the second actual abutment member. Thus, it is possible to suppress the moving away of the sheet member from at least one of the first temporary abutment member, the first actual abutment member, the second temporary abutment member, or the second actual abutment member due to the reaction of the sheet member abutting that abutment member. In this way, the sheet member can even more reliably abut at least one of the first temporary abutment member, the first actual abutment member, the second temporary abutment member, and the second actual abutment member, and the accuracy of positioning the sheet member can be improved even more.
The devices for positioning a sheet member of the first and second aspects of the present invention which have been described above usually further comprise a conveying member provided at a side of the plate, in a direction substantially orthogonal to the temporary direction, and due to conveying member movement, the conveying member pushes the sheet member and conveys the sheet member in the second direction, and after the sheet member abuts the reference abutment member, the conveying member moves away from the sheet member.
In the device for positioning a sheet member having such a conveying member, due to the conveying member moving, the conveying member pushes the sheet member and conveys the sheet member in the other direction. Thus, the sheet member can be reliably conveyed in this other direction. Moreover, the conveying member moves apart from the sheet member after the sheet member has abutted the reference abutment member. Thus, the conveying member does not restrain the sheet member. In this way, buckling deformation of the sheet member can be prevented, and the positioning accuracy can be improved even more.
In the device for positioning a sheet member of the second aspect of the present invention, usually, a position, at which the sheet member abuts the first actual abutment member at at least two points and abuts the reference abutment member, and a position, at which the sheet member abuts the second actual abutment member at at least two points and abuts the reference abutment member, are the same position.
In the device for positioning a sheet member of the second aspect of the present invention which has such a feature, the position, at which the sheet member abuts the first actual abutment member at at least two points and abuts the reference abutment member, and the position, at which the sheet member abuts the second actual abutment member at at least two points and abuts the reference abutment member, are the same position. Thus, even if the end surfaces of the sheet member are curved, the position at which the sheet member is positioned by the first actual abutment member and the reference abutment member, and the position at which the sheet member is positioned by the second actual abutment member and the reference abutment member, can be made to coincide.
Moreover, the above-described two positions at which the sheet member is positioned can be made to coincide, even if cut-outs are not formed in the sheet member as in the conventional art. Thus, a conventional, expensive cut-out forming device is not needed, and the device can be made to be lower cost.
A device for positioning a sheet member of the third aspect of the present invention comprises: a generally flat plate on which the sheet member is received; a first conveying device provided so as to correspond to the sheet member received on the plate, and conveying the sheet member in a predetermined direction; a first abutment member provided at a side of the plate, in the predetermined direction, and due to the sheet member being conveyed in the predetermined direction, the sheet member abutting the first abutment member at at least two points, which determines a position of the sheet member in a first direction; a second abutment member provided at that side of the plate, and due to the sheet member being conveyed in the predetermined direction, abutting the second abutment member at at least two points, which determines a position of the sheet member in a second direction; a second conveying device which, when the sheet member abuts the first abutment member, conveys the sheet member in a third direction substantially orthogonal to the first direction, and which, when the sheet member abuts the second abutment member, conveys the sheet member in a fourth direction substantially orthogonal to the second direction; and a third abutment member provided at sides of the plate, in the third direction and the fourth direction, and due to the sheet member being conveyed in one of the third direction and the fourth direction, the sheet member abutting the third abutment member, which determines a position of the sheet member in one of the third direction and the fourth direction, wherein a position at which the sheet member abuts the first abutment member at at least two points and abuts the third abutment member, and a position at which the sheet member abuts the second abutment member at at least two points and abuts the third abutment member, are substantially the same position.
In the device for positioning a sheet member of the third aspect of the present invention, the position of the sheet member in the first direction is determined by the first conveying device conveying, in the predetermined direction, the sheet member which is on the plate, and the sheet member abutting the first abutment member at at least two points. Moreover, the position of the sheet member in the third direction (i.e., the direction orthogonal to the first direction) is determined by the second conveying device conveying the sheet member in the third direction, and the sheet member abutting the third abutment member. In this way, the sheet member is positioned by the first abutment member and the third abutment member in a state in which the sheet member is received on the plate.
Moreover, the position of the sheet member in the second direction is determined by the first conveying device conveying the sheet member in the predetermined direction, and the sheet member abutting the second abutment member at at least two points. In addition, the position of the sheet member in the fourth direction (i.e., the direction orthogonal to the second direction) is determined by the second conveying device conveying the sheet member in the fourth direction, and the sheet member abutting the third abutment member. In this way, the sheet member is positioned by the second abutment member and the third abutment member in the state in which the sheet member is received on the plate.
Here, the position, at which the sheet member abuts the first abutment member at at least two points and abuts the third abutment member, and the position, at which the sheet member abuts the second abutment member at at least two points and abuts the third abutment member, are the same position. Thus, even if the end surfaces of the sheet member are curved, the position, at which the sheet member is positioned by the first abutment member and the third abutment member, and the position, at which the sheet member is positioned by the second abutment member and the third abutment member, can be made to coincide.
Moreover, the above-described two positions at which the sheet member is positioned can be made to coincide, even if cut-outs are not formed in the sheet member as in the conventional art. Thus, a conventional, expensive cut-out forming device is not needed, and the device can be made to be lower cost.
An image recording device of the fourth aspect of the present invention comprises: a generally flat plate on which a printing plate is received; a first conveying device provided so as to correspond to the printing plate received on the plate, and conveying the printing plate in a predetermined direction; a first abutment member provided at a side of the plate, in the predetermined direction, and due to the printing plate being conveyed in the predetermined direction, the printing plate abutting the first abutment member at at least two points, which determines a position of the printing plate in a first direction; a second abutment member provided at the side of the plate, and due to the printing plate being conveyed in the predetermined direction, the printing plate abutting the second abutment member at at least two points, which determines a position of the printing plate in a second direction; a second conveying device which, when the printing plate abuts the first abutment member, conveys the printing plate in a third direction substantially orthogonal to the first direction, and which, when the printing plate abuts the second abutment member, conveys the printing plate in a fourth direction substantially orthogonal to the second direction; a third abutment member provided at sides of the plate, in the third direction and the fourth direction, and due to the printing plate being conveyed in one of the third direction and the fourth direction, abutting the third abutment member after the third abutment member has moved from a starting point position in accordance with a size of the printing plate, which determines a position of the printing plate in one of the third direction and the fourth direction; and an image recording section provided so as to be movable from an origin position, and recording an image on the printing plate which has been positioned by abutting the second abutment member at at least two points and by abutting the third abutment member, wherein a position at which the printing plate abuts the first abutment member at at least two points and abuts the third abutment member, is substantially the same as where the printing plate abuts the second abutment member at at least two points and abuts the third abutment member, and an image recording start position of the printing plate is determined by computing an initial movement distance of the image recording section from the origin position, in accordance with a distance which the third abutment member has moved from the starting point position in accordance with the size of the printing plate.
In the image recording device of the fourth aspect of the present invention, the position of the printing plate in the first direction is determined by the first conveying device conveying, in the predetermined direction, the printing plate which is on the plate, and the printing plate abutting the first abutment member at at least two points. Moreover, the position of the printing plate in the third direction (i.e., the direction orthogonal to the first direction) is determined by the second conveying device conveying the printing plate in the third direction, and the printing plate abutting the third abutment member which has moved from its starting point position in accordance with the size of the printing plate. In this way, the printing plate is positioned by the first abutment member and the third abutment member in a state in which the printing plate is received on the plate.
The position of the printing plate in the second direction is determined by the first conveying device conveying the printing plate in the predetermined direction and the printing plate abutting the second abutment member at at least two points. Further, the position of the printing plate in the fourth direction (i.e., the direction orthogonal to the second direction) is determined by the second conveying device conveying the printing plate in the fourth direction, and the printing plate abutting the third abutment member which has moved from its starting point position in accordance with the size of the printing plate. In this way, the printing plate is positioned by the second abutment member and the third abutment member in a state in which the printing plate is received on the plate.
Moreover, the image recording section, which can move from its origin position, records an image on the printing plate which has been positioned by the second abutment member and the third abutment member.
Here, the position, at which the printing plate abuts the first abutment member at at least two points and abuts the third abutment member, and the position, at which the printing plate abuts the second abutment member at at least two points and abuts the third abutment member, are the same position. Thus, even if there is curving at the end surfaces of the printing plate, the position, at which the printing plate is positioned by the first abutment member and the third abutment member, and the position, at which the printing plate is positioned by the second abutment member and the third abutment member, can be made to coincide with each other.
Moreover, the above-described two positions at which the printing plate is positioned can be made to coincide, even if cut-outs are not formed in the printing plate as in the conventional art. Thus, a conventional, expensive cut-out forming device is not needed, and the device can be made to be lower cost.
Here, the image recording start position of the printing plate is determined by computing an initial moving distance of the image recording section from its origin position, in accordance with a distance which the third abutment member has moved from its starting point position in accordance with the size of the printing plate. Thus, the image recording start position of the printing plate can be determined accurately.
In the image recording device of the fourth aspect of the present invention, usually, punch holes, which are used in positioning for printing processing of the printing plate, are formed in the printing plate which has been positioned by abutting the first abutment member at at least two points and by abutting the third abutment member.
Usually, in the image recording device of the fourth aspect of the present invention, punch holes, which are used in positioning for printing processing of the printing plate, are formed in the printing plate which has been positioned by the first abutment member and the third abutment member. Further, as described above, the position at which the printing plate is positioned by the first abutment member and the third abutment member (the position at which the printing plate is positioned for punch hole punching), and the position at which the printing plate is positioned by the second abutment member and the third abutment member (the position at which the printing plate is positioned for image recording) coincide with one another. Thus, the image recording position of the printing plate can be made to coincide with the printing position of the printing plate determined by the punch holes.